/*
 * Copyright 2022 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package androidx.compose.ui.text.font

import android.content.Context
import android.content.res.Configuration
import android.graphics.fonts.FontStyle
import android.os.Build
import androidx.annotation.DoNotInline
import androidx.annotation.RequiresApi
import androidx.compose.ui.unit.Density

/**
 * Android implementation for [PlatformResolveInterceptor].
 *
 * Android system accessibility should be able to override any font metric that affects how
 * FontFamily is resolved. Font Size preference is handled by [Density.fontScale]. This interceptor
 * currently adjusts the Font Weight for Bold Text feature.
 */
internal data class AndroidFontResolveInterceptor(private val fontWeightAdjustment: Int) :
    PlatformResolveInterceptor {

    override fun interceptFontWeight(fontWeight: FontWeight): FontWeight {
        // do not intercept if fontWeightAdjustment is not set or undefined
        if (
            fontWeightAdjustment == 0 ||
                fontWeightAdjustment == Configuration.FONT_WEIGHT_ADJUSTMENT_UNDEFINED
        ) {
            return fontWeight
        }

        val finalFontWeight =
            (fontWeight.weight + fontWeightAdjustment).coerceIn(
                FontStyle.FONT_WEIGHT_MIN,
                FontStyle.FONT_WEIGHT_MAX,
            )
        return FontWeight(finalFontWeight)
    }
}

/** A helper function to create an interceptor using a context. */
internal fun AndroidFontResolveInterceptor(context: Context): AndroidFontResolveInterceptor {
    val fontWeightAdjustment = FontWeightAdjustmentHelper.getFontWeightAdjustment(context)
    return AndroidFontResolveInterceptor(fontWeightAdjustment)
}

internal object FontWeightAdjustmentHelper {
    fun getFontWeightAdjustment(context: Context): Int =
        when {
            Build.VERSION.SDK_INT >= 31 ->
                FontWeightAdjustmentHelperApi31.fontWeightAdjustment(context)
            else -> 0
        }
}

@RequiresApi(31)
internal object FontWeightAdjustmentHelperApi31 {
    @DoNotInline
    @RequiresApi(31)
    fun fontWeightAdjustment(context: Context): Int =
        context.resources.configuration.fontWeightAdjustment
}
